silkie

A mythological creature of celtic/irish mythology. (Also commonly spelled selkie.) They are a shapeshifter race, normally in seal form, but occasionally assuming a human body. They can be told from normal humans by their incredibly soulful eyes and innate longing for the sea.

There are many legends following this theme:
there is a barren couple who wishes for nothing more than a child. They pray to the gods, and one day the husband, usually a fisherman, somehow on the beach or rock cliffs, hears a child crying and finds instead a lost seal pup. Upon taking it home and caring for it, it slowly transforms into a human baby. They thank the gods for the blessing and raise the child as their own, knowing if he ever sets foot in the sea again, he will revert permanently to seal form.

Years go by, and the child grows into a strong young lad. One day, his fisherman father goes out in a bad storm, because they need the fish for food. The weather become worse than he, in all his skill, can handle and his boat capsizes. The son, with his supernatural hearing, hears his father call, from the house. He knows he will have to leave the life and family he loves, but his father will drown if he does nothing. So the boy dives into the ocean, swims to where his father is, and helps him to shore, his reversion to seal half-complete. He lived in the sea from then on, but once every so often an old couple could be seen by the shore, talking lovingly to a seal with amazingly wise and amazingly human eyes.